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ACS706ELC-05C中文资料

NOTE: For detailed information on purchasing options, contact your local Allegro field applications engineer or sales representative.

Allegro MicroSystems, Inc. reserves the right to make, from time to time, revisions to the anticipated product life cycle plan for a product to accommodate changes in production capabilities, alternative product availabilities, or market demand. The information included herein is believed to be accurate and reliable. However, Allegro MicroSystems, Inc. assumes no respon-sibility for its use; nor for any infringements of patents or other rights of third parties which may result from its use.

Recommended Substitutions:

For existing customer transition, and for new customers or new appli-cations, refer to the ACS712.

Bidirectional 1.5 mΩ Hall Effect Based Linear Current Sensor

with V oltage Isolation and 15 A Dynamic Range

ACS706ELC-05C

Date of status change: December 26, 2006

These parts are in production but have been determined to be

NOT FOR NEW DESIGN. This classification indicates that sale of this device is currently restricted to existing customer applications. The device should not be purchased for new design applications because obsolescence in the near future is probable. Samples are no longer available.

Not for New Design

Features and Benefits

? Small footprint, low-profile SOIC8 package

? 1.5 m Ω internal conductor resistance

? Excellent replacement for sense resistors ? 1600 V RMS minimum isolation voltage between pins 1-4 and 5-8? 4.5 to 5.5 V, single supply operation ? 50 kHz bandwidth

? 133 mV/A output sensitivity and 15 A dynamic range ? Output voltage proportional to ac and dc currents ? Factory-trimmed for accuracy

? Extremely stable output offset voltage ? Near-zero magnetic hysteresis

? Ratiometric output from supply voltage

The Allegro ACS706 family of current sensors provides economical and

precise solutions for current sensing in industrial, automotive, commercial, and communications systems. The device package allows for easy implementation by the customer. Typical applications include motor control, load detection and management, switched-mode power supplies, and overcurrent fault protection.

The device consists of a precision, low-offset linear Hall sensor circuit with a copper conduction path located near the surface of the die. Applied current flowing through this copper conduction path generates a magnetic field which is sensed by the integrated Hall IC and converted into a proportional voltage. Device accuracy is optimized through the close proximity of the magnetic signal to the Hall transducer. A precise, proportional voltage is provided by the low-offset, chopper-stabilized BiCMOS Hall IC, which is programmed for accuracy at the factory.

The output of the device has a positive slope (>V CC / 2) when an increasing current flows through the primary copper conduction path (from pins 1 and 2, to pins 3 and 4), which is the path used for current sensing. The internal resistance of this conductive path is typically 1.5 m Ω, providing low power loss. The thickness of the copper conductor allows survival of the device at up to 5× overcurrent conditions. The terminals of the conductive path are electrically isolated from the sensor leads (pins 5 through 8). This allows the ACS706 family of sensors to be used in applications requiring electrical isolation without the use of opto-isolators or other costly isolation techniques.

The ACS706 is provided in a small, surface mount SOIC8 package. The leadframe is plated with 100% matte tin, which is compatible with standard lead (Pb) free printed circuit board assembly processes. Internally, the flip-chip uses high-temperature Pb-based solder balls, currently exempt from RoHS. The device is fully calibrated prior to shipment from the factory.

Use the following complete part number when ordering:

Part Number

Package

ACS706ELC-05C

SOIC8 surface mount

Bidirectional 1.5 m Ω Hall Effect Based Linear Current Sensor

with Voltage Isolation and 15 A Dynamic Range

Functional Block Diagram

0.1 μF

PERFORMANCE CHARACTERISTICS, over operating ambient temperature range, unless otherwise specified

Propagation Time t PROP I P =±5 A, T A = 25°C– 3.15–μs Response Time t RESPONSE I P =±5 A, T A = 25°C–6–μs Rise Time t r I P =±5 A, T A = 25°C–7.45–μs Frequency Bandwidth f–3 dB, T A = 25°C; I P is 10 A peak-to-peak; no external filter–50–kHz

Sensitivity Sens Over full range of I P , I P applied for 5 ms; T A = 25°C–133–mV/A Over full range of I P , I P applied for 5 ms124–142mV/A

Noise V NOISE Peak-to-peak, T A = 25°C, no external filter–90–mV Root Mean Square, T A = 25°C, no external filter–16–mV

Linearity E LIN Over full range of I P , I P applied for 5 ms–±1±4.7% Symmetry E SYM Over full range of I P , I P applied for 5 ms98100104.5% Zero Current Output Voltage V OUT(Q)I P = 0 A, T A = 25°C–V CC / 2–V

Electrical Offset Voltage V OE I P = 0 A, T A = 25°C–15–15mV I P = 0 A–65–65mV

Magnetic Offset Error I ERROM I P = 0 A, after excursion of 5 A–±0.01±0.05A

Total Output Error1E TOT I P =±5 A, I P applied for 5 ms;T A = 25°C–±1.5–% I P = ±5 A, I P applied for 5 ms––±12.5%

Characteristic Symbol Test Conditions Min.Typ.Max.Units ELECTRICAL CHARACTERISTICS, over operating ambient temperature range unless otherwise specified

Optimized Accuracy Range I P–5–5A Linear Sensing Range I R–15–15A Supply Voltage V CC 4.5 5.0 5.5V Supply Current I CC V CC = 5.0 V, output open5810mA Output Resistance R OUT I OUT = 1.2 mA–12ΩOutput Capacitance Load C LOAD VOUT to GND––10nF Output Resistive Load R LOAD VOUT to GND 4.7––kΩPrimary Conductor Resistance R PRIMARY T A = 25°C– 1.5–mΩRMS Isolation Voltage V ISORMS Pins 1-4 and 5-8; 60 Hz, 1 minute16002500–V DC Isolation Voltage V ISODC–5000–V OPERATING CHARACTERISTICS

THERMAL CHARACTERISTICS2,3, T A = –40°C to 125°C, V CC = 5 V unless otherwise specified

–Value–Units

Junction-to-Lead Thermal Resistance RθJL

Mounted on the Allegro ASEK 70x evaluation board; additional

information about reference boards and tests is available on the

Allegro Web site

–5–°C/W

Junction-to-Ambient Thermal Resistance RθJA

Mounted on the Allegro ASEK 70x evaluation board; additional

information about reference boards and tests is available on the

Allegro Web site

–41–°C/W

1Percentage of I P, with I P = 5 A. Output filtered. Up to a 2.0% shift in E TOT may be observed at end-of-life for this device.

2 The Allegro evaluation board has 1500 mm2 of 2 oz. copper on each side, connected to pins 1 and 2, and to pins

3 and 4, with thermal vias connect-ing the layers. Performance values include the power consumed by the PWB. Further details on the board are available from the ACS70

4 Frequently Asked Questions document on our website. Further information about board design and thermal performance also can be found on pages 16 and 17 of this datasheet.

3RθJA values shown in this table are typical values, measured on the Allegro evaluation board. The actual thermal performance depends on the board design, the airflow in the system, and thermal interactions between the sensor and surrounding components through the PCB and the ambient air. To improve thermal performance, see our applications material on the Allegro Web site.

Typical Performance Characteristics

-50

-25

100

125

150

Supply Current versus Ambient Temperature

V CC = 5 V

T A (°C)

I C C (m A )

4.5

4.6

4.7

4.8

4.9

5 5.1

5.2

5.3

5.4

5.5

V CC (V)

I C C (m A )

8.00

8.058.108.158.208.258.308.358.408.458.50Supply Current versus Applied V

11.01.5

2.02.5

3.03.5

4.0-9

-8-7-6-5-4-3-2-10123456789

V O U T (V )

Output Voltage versus Primary Current

V CC = 5 V

I P (A)

110

115120125130135140145

150160S e n s (m V /A )

-9

-8

-7

-6

-5

-4

-3

-2

-1

789

I P (A)

Sensitivity versus Primary Current

V CC = 5 V

-50

-250255075100125150

V O U T (Q ) (V )

2.470

2.580

2.490

2.500

2.510

2.520

2.530

Zero Current Output Voltage vs. Ambient Temperature

T A (°C)

I P = 0 A

Zero Current Output Currrent versus Ambient Temperature

(Data in above chart converted to amperes)

= 0 A

I V O U T (Q ) (A )

–0.3

–0.2

–0.1

0.1

0.2

0.3

–50

–25

100

125

150

T A (°C)

V O M (m A )

-1.0-0.8-0.6-0.4-0.200.20.40.60.81.0-50

-25

5075

150

100

125

T A (°C)

Magnetic Offset Error versus Ambient Temperature

V CC = 5 V; I P

= 0 A, after excursion to 5 A

-50

-25

150

100

125

T A (°C)

00.51.01.52.02.5

3.0E L I N (%)

Nonlinearity versus Ambient Temperature

V CC = 5 V I P

= 5 A

Measurements taken at T A = –40, 25, –20, 85 and 125°C

Typical Percentage Error versus Ambient Temperature

E T O T (% o f 5 A )

T A (°C)

-15

-10

-5

-50-250255075100125150

Typical Peak-to-Peak Noise of ACS706ELC-05C at T A =25°C

Step Response of ACS706ELC-05C at T A =25°C

ACS706 Output (mV)

5 A Excitation Signal

Time = 10 μs/div.

Excitation signal = 1.00 A/div.Output = 100 mV/div.

Time = 20 μs/div.

Noise = 20.0 mV/div.

ACS706ELC-05C Noise Filtering and Frequency Response Performance Break Frequency

of Filter on Output

(kHz)Resistance

(kΩ)

Capacitance

(μF)

Nominal

Programmed

Sensitivity

(mV/A)

Filtered

Peak-to-

Peak Noise

(mV)

Resolution

with Filtering

(A)

Rise Time

for 5A Step,

Filtered

(μs)

Unfiltered––

133 900.6777.45

800.200

0.01 75.90.5718.26

500.32064.70.48610.08 400.39260.30.45311.39 200.80043.30.32617.56 10 1.628.90.21831.96 7.0 3.1518.30.13754.55 3.3 4.813.80.10481.77 0.626 1.90.015404.16 0.3530.760.00573732.89

Sensitivity (Sens). The change in sensor output in response to a 1 A change through the primary conductor. The sensitivity is the prod-uct of the magnetic circuit sensitivity (G / A ) and the linear IC amplifier gain (mV/G). The linear IC amplifier gain is programmed at the factory to optimize the sensitivity (mV/A) for the full-scale current of the device.

Noise (V NOISE ). The product of the linear IC amplifier gain (mV/G) and the noise floor for the Allegro Hall effect linear IC (≈1 G). The noise floor is derived from the thermal and shot noise observed in Hall elements. Dividing the noise (mV) by the sensitivity (mV/A) provides the smallest current that the device is able to resolve.

Linearity (E LIN ): The degree to which the voltage output from the sensor varies in direct proportion to the primary current through its full-scale amplitude. Nonlinearity in the output can be attributed to the saturation of the flux concentrator approaching the full-scale current. The following equation is used to derive the linearity:

Definitions of Accuracy Characteristics

1001–

[

{[{

V out_full-scale amperes –V OUT(Q)()2 (V out_half-scale amperes –V OUT(Q))

100

where V out_full-scale amperes = the output voltage (V) when the sensed current approximates full-scale ±I P .

Symmetry (E SYM ). The degree to which the absolute voltage output from the sensor varies in proportion to either a positive or nega-tive full-scale primary current. The following formula is used to derive symmetry:

Quiescent output voltage (V OUT(Q)). The output of the sensor when the primary current is zero. For a unipolar supply voltage, it

nominally remains at V CC ? 2. Thus, V CC = 5 V translates into V OUT(Q) = 2.5 V . Variation in V OUT(Q) can be attributed to the resolution of the Allegro linear IC quiescent voltage trim and thermal drift.

Electrical offset voltage (V OE ). The deviation of the device output from its ideal quiescent value of V CC / 2 due to nonmagnetic causes. To convert this voltage to amperes, divide by the device sensitivity, Sens.

Accuracy (E TOT ). The accuracy represents the maximum deviation of the actual output from its ideal value. This is also known as the total ouput error. The accuracy is illustrated graphically in the Output V oltage versus Current chart on the following page.Accuracy is divided into four areas:

? 0 A at 25°C. Accuracy of sensing zero current flow at 25°C, without the effects of temperature.? 0 A over Δ temperature. Accuracy of sensing zero current flow including temperature effects.

? Full-scale current at 25°C. Accuracy of sensing the full-scale current at 25°C, without the effects of temperature.? Full-scale current over Δ temperature. Accuracy of sensing full-scale current flow including temperature effects.

Ratiometry . The ratiometric feature means that its 0 A output, V OUT(Q), (nominally equal to V CC /2) and sensitivity, Sens, are propor-tional to its supply voltage, V CC . The following formula is used to derive the ratiometric change in 0 A output voltage, ΔV OUT(Q)RAT (%):

100

V OUT(Q)VCC /V OUT(Q)5V

V CC /5 V

‰

The ratiometric change in sensitivity, ΔSens RAT (%), is defined as:

100

Sens VCC /Sens 5V

V CC /5 V

‰

Output voltage vs. current, illustrating sensor accuracy at 0 A and at full-scale current

Definitions of Dynamic Response Characteristics

Propagation delay (t PROP): The time required for the sensor output to reflect a change in the primary cur-

rent signal. Propagation delay is attributed to inductive loading within the linear IC package, as well as in the inductive loop formed by the primary conductor geometry. Propagation delay can be considered as a fixed time offset and may be compensated.

Response time (t RESPONSE): The time interval between a) when the primary current signal reaches 90% of its final value, and b) when the sensor reaches 90% of its output corresponding to the applied current.

Rise time (t r): The time interval between a) when the sensor reaches 10% of its full scale value, and b) when it reaches 90% of its full scale value. The rise time to a step response is used to derive the bandwidth of the current sensor, in which ?(–3 dB) = 0.35 / t r. Both t r and t RESPONSE are detrimentally affected by eddy current losses observed in the conductive IC ground plane.

Device Branding Key (Two alternative styles are used)

ACS706T ELC05C YYWWA ACS Allegro Current Sensor

706Device family number

T Indicator of 100% matte tin leadframe plating

E Operating ambient temperature range code

LC Package type designator

05C Primary sensed current

YY Manufacturing date code: Calendar year (last two digits) WW Manufacturing date code: Calendar week

A Manufacturing date code: Shift code

ACS706T ELC05C

L...L YYWW

ACS Allegro Current Sensor

706Device family number

T Indicator of 100% matte tin leadframe plating

E Operating ambient temperature range code

LC Package type designator

05C Primary sensed current

L...L Manufacturing lot code

YY Manufacturing date code: Calendar year (last two digits)

WW Manufacturing date code: Calendar week Standards and Physical Specifications

Parameter Specification

Flammability (package molding compound)UL recognized to UL 94V-0

Fire and Electric Shock UL60950-1:2003

EN60950-1:2001

CAN/CSA C22.2 No. 60950-1:2003

Hall Chopper Stabilization Technique

Chopper Stabilization is an innovative circuit technique that is used to minimize the offset voltage of a Hall element and an associated on-chip amplifier. Allegro patented a Chopper Stabilization technique that nearly eliminates Hall IC output drift induced by temperature or package stress effects. This offset reduction technique is based on a signal modulation-demodulation process. Modulation is used to separate the undesired dc offset signal from the magnetically induced signal in the frequency domain. Then, using a low-pass filter, the modu-lated dc offset is suppressed while the magnetically induced signal passes through the filter. As a result of this chopper stabilization approach, the output voltage from the Hall IC is desensitized to the effects of temperature and mechanical stress. This technique produces devices that have an extremely stable Electrical Offset V oltage, are immune to thermal stress, and have precise recoverability after temperature cycling.

This technique is made possible through the use of a BiCMOS process that allows the use of low-offset and low-noise amplifiers in combination with high-density logic integration and sample and hold circuits.

Concept of Chopper Stabilization Technique

Applications Information

In order to quantify transient common-mode voltage rejection for the ACS706, a device was soldered onto a printed circuit board. A 0.1 μF bypass capacitor and a 5 V dc power supply were connected between VCC and GND (pins 8 and 5) for this device. A 10 k Ω load resistor and a 0.01 μF capacitor were connected in parallel between the VOUT pin and the GND pin of the device (pins 7 and 5).

A function generator was connected between the primary current conductor (pins 1 thru 4) and the GND pin of the device (pin 5). This function generator was configured to generate a 10 V peak (20 V peak-to-peak) sine wave between pins 1-4 and pin 5. Note that the sinusoidal stimulus was applied such that no electrical current would flow through the copper conductor composed of pins 1-4 of this device.

The frequency of this sine wave was varied from 60 Hz to 5 MHz in discrete steps. At each frequency, the statistics feature of an oscilloscope was used to measure the voltage variations (noise) on the ACS706 output in mV (peak to peak). The noise was measured both before and after the application of the stimulus. Transient common-mode voltage rejection as a function of frequency is shown in the following figure.

Transient Common-Mode Voltage Rejection in the ACS706

(kHz)

Frequency of 20 V Peak-to-Peak Stimulus –60

–55–50–45–40–35–30T r a n s i e n t R e j e c t i o n (d B )

The Effect of PCB Layout on ACS706 Thermal Performance

Eight different PC boards were fabricated to characterize the effect of PCB design on the operating junction temperature of the Hall-effect IC inside of the ACS706. These PC boards are shown in the figure below.

An ACS706 device was soldered on to each PCB for thermal testing. The results of the testing are shown in the following table.

Test Results on Eight Thermal Characterization PCBs

Tested at 15A, T A = 20°C, still air, 2 oz. copper traces, current carried on and off board by 14 gauge wires PC Boards Sides with Traces

Trace Width (mm)

Trace Length (mm)

Temperature Rise Above Ambient (°C)

50901.550Overheated

410481.5101102

50531.550106410381.5

Improved PC Board Designs

The eight PC boards in the figure above do not represent an ideal PC board for use with the ACS706. The ACS706 evaluation boards, for sale at the Allegro Web site On-Line Store, represent a more optimal PC board design (see photo below). On the evaluation boards, the current to be sensed flows through very wide traces that were fabricated using 2 layers of 2 oz. copper. Thermal management tests were conducted on the Allegro evaluation boards and all tests were performed using the same test conditions described in the bulleted list above. The results for these thermal tests are shown in the table below. When using the Allegro evaluation boards we see that even at an applied current of 20 A the junction temperature of the ACS706 is only ≈30 degrees above ambient temperature.

Test Results on Eight Electrical Characterization PCBs

Tested at T A = 20°C, still air

Applied Current

(A)Temp Rise Above Ambient

(°C)

1522

2031

Allegro Current sensor evaluatin board with ACS706 and external connections.

The products described herein are manufactured under one or more of the following U.S. patents: 5,045,920; 5,264,783; 5,442,283; 5,389,889; 5,581,179; 5,517,112; 5,619,137; 5,621,319; 5,650,719; 5,686,894; 5,694,038; 5,729,130; 5,917,320; and other patents pending.

Allegro MicroSystems, Inc. reserves the right to make, from time to time, such de p ar t ures from the detail spec i f i c a t ions as may be required to permit improvements in the per f or m ance, reliability, or manufacturability of its products. Before placing an order, the user is cautioned to verify that the information being relied upon is current.

Allegro products are not authorized for use as critical components in life-support devices or sys t ems without express written approval. The in f or m a t ion in c lud e d herein is believed to be ac c u r ate and reliable. How e v e r, Allegro MicroSystems, Inc. assumes no re s pon s i b il i t y for its use; nor for any in f ringe m ent of patents or other rights of third parties which may result from its use. Copyright?2005, Allegro MicroSystems, Inc.

Package LC, 8-pin SOIC

Preliminary dimensions, for reference only Dimensions in millimeters

(reference JEDEC MS-012 AA)

A Terminal #1 mark area